LPG conversion to GS450H

Britprius · July 11, 2017

Has anyone converted a GS450H to LPG. From what I have gathered it seems that it is problematic because the possibility of melting the direct injection injectors.

Any help would be appreciated.

John.

Farqui · July 11, 2017

Are you looking for another project John?

Upex · July 11, 2017

I've had manly cars and they have seen 100k, 200k plus miles without the slightest issue. Albeit not di engines, there surely can't be that much difference to melt di but be fine for many trips round the globe for others?

Surely the key is a good closed loop system (only ever had prins myself, plus one other I can't recall) and good servicing, albeit lpg offers less top end lubrication than petrol and can cause value issues, so perhaps this is what causes issues with di engines?

I'm not clued up enough to comment really thinking it through, so just ignore me!

Britprius · July 11, 2017

5 hours ago, Farqui said:

Are you looking for another project John?

Next project is android display on OEM screen. However an LPG conversion is possibly on the cards.

John.

Britprius · July 11, 2017

38 minutes ago, Upex said:

I've had manly cars and they have seen 100k, 200k plus miles without the slightest issue. Albeit not di engines, there surely can't be that much difference to melt di but be fine for many trips round the globe for others?

Surely the key is a good closed loop system (only ever had prins myself, plus one other I can't recall) and good servicing, albeit lpg offers less top end lubrication than petrol and can cause value issues, so perhaps this is what causes issues with di engines?

I'm not clued up enough to comment really thinking it through, so just ignore me!

Well I'm a complete novice with LPG apart from one vehicle back in the 1970's. I had an Austin 1800 converted with the old purely mechanical diaphragm system. This worked well on the BMC B series engine.

The problem as I understand it with DI Lexus engines is that LPG burns hotter than petrol. Plus you loose the cooling effect on combustion of the petrol vaporising in the combustion chambers of the 13 to 1 compression ratio engine. With no fuel flow through the injectors they are also not cooled by the fuel. The inlet tract injectors are not affected.

I would like to be proved wrong, but do not want to go to an installer that just wants to sell me a system that is going to prove troublesome in the future.

John

Bluesman · July 11, 2017

LPG doesnt burn as hot as petrol. The problem with some Lexus engines is getting the EMU to work with it. If you can get it installed they are brilliant on LPG.

Your biggest problem will be getting a decent outfit to install it. You can pay thousands but if they mess the install up you might just as well send me all the money, I get to have a good time on it and you get to keep your beloved Lexus with you driving it.

Farqui · July 11, 2017

LPG is a fascinating subject and has several challenges to overcome. Combined fueling now seems to be a viable option, to add petrol and lube the valves when idling or under high load.

In the GS 450H I'm not sure where you'll be able to add a LPG tank and retain some boot space. The boot is already on the small size.

The fuel savings are tempting but some places restrict LPG vehicles e.g. Le Shuttle 😢 Which we'd find a bore.

alexchrisro · July 11, 2017

In my country there are a lot of Lexus with lpg specially the RX model. I personally saw a GS450h with lpg with 150.000 miles. Car runs great and the engine runs a bit smoother then gasoline.

sorcerer · July 12, 2017

@Britprius Please contact me off the forum at jhewitt1958@gmail.com

I should be able to help you with some information about this.

Cheers,

John

Britprius · July 12, 2017

12 hours ago, Farqui said:

LPG is a fascinating subject and has several challenges to overcome. Combined fueling now seems to be a viable option, to add petrol and lube the valves when idling or under high load.

In the GS 450H I'm not sure where you'll be able to add a LPG tank and retain some boot space. The boot is already on the small size.

The fuel savings are tempting but some places restrict LPG vehicles e.g. Le Shuttle 😢 Which we'd find a bore.

The fuel tank would go in the spare wheel well "a tank here would hold circa 60Ltrs" I do not mind loosing this as when I am touring with my caravan the spare wheel could go in the locker on the caravan. I also carry a mini compressor, and a can of sealant that would get me out of trouble in most situations.

Since I have no intention of using the shuttle this does not really come into the equation, but I know this is a problem to some. It does seem a bit strange when they allow bottles of gas to be carried in motor homes, and caravans.

John.

Farqui · July 12, 2017

I hadn't realised that the spare wheel well could carry so many litres. That'd pretty much double the cars range.

Good call, my previous car carried sealant and a compressor instead of a spare and thankfully we never needed to use it. So we probably saved a few quid not hauling around a spare over the years. Spare wheels are often dropped in order to get the vehicle stat's inline with the latest reg's.

Good luck making progress with this. Beware tho, Robb will want you to start a mod thread ;)

Bluesman · July 12, 2017

6 hours ago, Farqui said:

I hadn't realised that the spare wheel well could carry so many litres. That'd pretty much double the cars range.

Good call, my previous car carried sealant and a compressor instead of a spare and thankfully we never needed to use it. So we probably saved a few quid not hauling around a spare over the years. Spare wheels are often dropped in order to get the vehicle stat's inline with the latest reg's.

Good luck making progress with this. Beware tho, Robb will want you to start a mod thread ;)

I have an 80 litre tank in my spare wheel well. It only sticks proud of the boot floor by about a quarter of an inch.

Britprius · July 14, 2017

Having now conversed with a couple of highly recommended installers I can confirm that both agree engines with direct injection are problematic for LPG conversion.

The consensus seems to be that even when running on LPG a small amount of petrol is injected through the DI injectors to help cool them. This means some of the gains from LPG are lost, but it still may be viable.

John.

Bluesman · July 14, 2017

1 hour ago, Britprius said:

Having now conversed with a couple of highly recommended installers I can confirm that both agree engines with direct injection are problematic for LPG conversion.

The consensus seems to be that even when running on LPG a small amount of petrol is injected through the DI injectors to help cool them. This means some of the gains from LPG are lost, but it still may be viable.

John.

In spite of the recent rumour that Profess had closed down I spoke with Andrew nyesterday and nothing could be further from the truth. They are having the workshops upgraded and reopen for installations again the 2nd week in August, they are however still open for the sale of LPG and minor repairs. I didnt ask him regarding the winding up documents with companies house as it is a matter between him his accountant, creditors, etc and has nothing to do with me or anyone else but its not unusual if you have more than one company to pull them all together under one roof. The main thing is Profess are still there.

Hangie · July 14, 2017

Don't forget that Gs450h got both direct and indirect injectors so whole system got extra complexity.

i always though that hybrid system would be the bigger challenge for the lpg ecru to handle with the constant change of the engine state.

sorcerer · July 14, 2017

2 minutes ago, Hangie said:

i always though that hybrid system would be the bigger challenge for the lpg ecru to handle with the constant change of the engine state.

I'm no expert by any means but I don't think so, not in that context anyway. The car ECU still sends signals to the petrol injectors but the LPG system captures those signals and diverts them to the LPG ECU and injectors instead. Whatever the car would do, the car still thinks and believes it is doing on petrol, so if it's in hybrid mode and then it needs to fire up the engine, the car will send the signals to fire up the engine and it will do - but just on gas rather than petrol.

Like I say though I have no idea what I'm talking about really, I just drive a non-hybrid LPG-powered car but I really don't know how it works - black magic and witchcraft come to mind

tonyricha · July 14, 2017

If LPG actually worked why would car manufacturers mess about with petrol/diesel/hybrid systems? Surley if they could market a luxury vehicle which runs reliably on half price fuel they would all offer it ?My LPG converted GS 300 burnt it's valves out twice in 1 year

Avoid.

Bluesman · July 14, 2017

7 minutes ago, tonyricha said:

If LPG actually worked why would car manufacturers mess about with petrol/diesel/hybrid systems? Surley if they could market a luxury vehicle which runs reliably on half price fuel they would all offer it ?My LPG converted GS 300 burnt it's valves out twice in 1 year

Avoid.

Thats strange as I have driven LPG cars which includes a car for my wife for the last 16+ years and I have never had any valve problems with any of them. If they have the harden valve seats which have been done on modern engines since before the loss of leaded petrol on the forcourts then you wont get any problem so what ever it was burning your valves it was a;most certainly not LPG.

sorcerer · July 14, 2017

41 minutes ago, tonyricha said:

If LPG actually worked why would car manufacturers mess about with petrol/diesel/hybrid systems? Surley if they could market a luxury vehicle which runs reliably on half price fuel they would all offer it ?My LPG converted GS 300 burnt it's valves out twice in 1 year

Avoid.

To answer your question, some manufacturers did produce LPG cars (Vauxhall and Volvo amongst them) but they never really sold in great numbers because the great British public never really took to LPG and some people are actually quite scared of it. I'm not sure of the history and timelines but I can say that LPG systems have improved in huge leaps and bounds and to compare modern systems to those of, say, 10 or 15 years ago is like comparing chalk and cheese.

I used to have a Nissan Maxima QX 3.0 SEL (Nissan's equivalent of the Lexus LS400) and covered more than 110,000 miles on LPG without a single problem. No loss of performance, no loss of power, seamless changeover from petrol to gas with no jerking or stumbling (and back again if I was silly enough to run out of gas) and no engine problems. Gas is better for the engine (9k miles between oil changes and using LPG the oil comes out almost as clean as it went in), better for the environment and much better on the wallet!

My installer did say that almost all Jap engines need Flashlube (or similar) to avoid valve seat recession so I made sure it never ran out of that and I had no problems. Maybe your installer either didn't do the job right or didn't match the LPG system to the car properly or didn't set it up correctly? I have no idea why you had such trouble but I can categorically say that that is not normal and something was definitely wrong.

I've now done over 13,000 miles in my RX300 since it was converted last year and it runs like a dream - looking forward to many more cheap miles to come

wow300 · July 26, 2017

On 14/07/2017 at 11:09 PM, Bluesman said:

Thats strange as I have driven LPG cars which includes a car for my wife for the last 16+ years and I have never had any valve problems with any of them. If they have the harden valve seats which have been done on modern engines since before the loss of leaded petrol on the forcourts then you wont get any problem so what ever it was burning your valves it was a;most certainly not LPG.

I have also been running LPG cars for over 15 yrs and never had a valve problem, they start up on petrol which lubricates the valves, they don't change over to LPG until water temp reaches about 70c this can vary as it's set up with the log ecu, if worried about valves just run it on petrol sometimes.

Always get a good installer tho, I use Ozone in plymouth, they know there onions on Lpg and also good mechanics.

Direct injection cannot be converted to LPG yet, although there are companies that are starting to make specific kits for specific cars but not many, and no one has done one for and DI lexus yet.